1. Field of the Invention
The present invention relates to a method for cleaning a probe of a probe card used for testing semiconductor wafers, and an apparatus for carrying out the method.
2. Description of the Related Art
In general, as disclosed in Japanese Unexamined Patent Publication No. 3-278438 and shown in FIG. 4, a probe card 1 used for testing semiconductor wafers is connected to a tester 4 through a contact ring 3 with contact pins 2. Further, a plurality of tungsten probes 6 are embedded in the lower portion of the probe card 1 so as to correspond to the number and positions of pads 5a of a semiconductor wafer 5 to be tested. On performing a predetermined test, a stage 7 on which the semiconductor wafer 5 is placed is raised from beneath the probe card 1, and the semiconductor wafer 5 is electrically connected to the tester 4 by contacting the pads 5a of the semiconductor wafer 5 to the probes 6 of the probe card 1, respectively.
When such a test is repeated, for example, aluminum as the material for the pads 5a adheres to probes 6, and the adhering aluminum is oxidized to form insulating surface coatings on the probes, which can render the test less reliable by inhibiting electrical contact. To avoid this, a non-illustrated cleaning apparatus is usually disposed near the testing apparatus, and the probes 6 are mechanically polished with the cleaning apparatus to remove aluminum adhering to the probes.
Hitherto, since probes 6 of such a probe card 1 are cleaned according to mechanical polishing using a cleaning apparatus as described above, the probes 6 are frequently deformed due to the application of forces to the probes 6 during polishing, so the probes 6 do not correspond to the positions of pads 5 of a semiconductor wafer 5 any longer, and, as a result, the electrical contact between the probes and the pads becomes imperfect. Accordingly, reliability in testing wafers is still reduced even if the probes are cleaned.